1. Field of the Invention
This invention has to do with the distribution of a chemical foam fire suppression product used to deprive a fire of oxygen. The foam product distribution system is used in airport terminals to aircraft boarding bridge situations to deliver the foam to the area on the ground immediately below the passenger boarding bridge.
2. Description of the Prior Art
In state of the art installations at airports where passenger boarding bridges are used, large municipal airports, for instance, fire protection is commonly provided by means of stand-alone fire fighting equipment, sometimes including foam generating equipment, in the vicinity of the passenger boarding bridges. In addition it is usual for mobile foam delivery fire fighting apparatus to be readily available at airports to fight the category of rites experienced at airports and around aircraft and aviation fuels. Safety and fire control personnel at airports are well aware of the use of foam to fight fires at airports.
A standard for the protection of passenger boarding bridges is published by the National Fire Protection Association. This standard is Referred to as NFPA 417. In this standard there is a section, Section 4-1.3, relating to "Fixed Foam Systems." It states, in part, in the 1990 edition of the standard, "When a fixed foam system is installed, the protection shall be adequate to blanket the area under the walkway [passenger boarding bridge] when positioned at the aircraft exit doors and for a distance of approximately 10 ft (3 m) in all directions." The standard continues but nowhere in the standard is there a teaching of how the fixed foam system standard can be implemented. In other words there is nothing in the standard that teaches the invention presented herein.
The prior art teaches automatic actuation of foam distributing equipment and is, for instance, mentioned in the standard referred to above.
In the early 1980's one of the two inventors of the foam delivery system disclosed herein had the idea, along with another person who worked for a chemical company that supplied foaming agents to industry, of having a foam dispensing nozzle attached to the inner end of a passenger boarding bridge. It was thought at that time that the use of a foaming agent, delivered from a fire extinguishing system beneath a passenger boarding bridge with a delivery nozzle that rotated with the bridge at the rotunda end of the bridge, was not patentable because foam for fire control was well known at airports.
One difficulty experienced with foam delivery systems under passenger boarding bridges was that the bridge sections telescoped within each other preventing the mounting of fixed foam distribution nozzles to the bridge sections.
The invention presented here represents an improvement to that early invention. One element of this invention is the provision of the telescoping foam delivery conduit that gets the foam from the inboard end of the passenger boarding bridge to the outboard end of the bridge. Another improvement is that the bridge presented here has a multiple nozzle foam discharge manifold mounted to the underside of the outermost bridge section. These and other advantages of the foam delivery system will be discussed in this specification.